Enhancing metallurgical and mechanical properties of friction stir lap welding of Al–Cu using intermediate layer

Abstract

In this paper, the material behaviour and mechanical characteristics of lap joint friction stir welding (FSW) between dissimilar alloys, namely, Cu and Al, is investigated. In order to produce welds of a higher quality, a layer of Cu is anodised on the aluminium alloy. The mechanical and the microstructural characterisations are performed on the welds, which are produced using various welding parameters. Scanning electron microscope with energy dispersive X-ray spectroscopy is used to identify the elemental compositions of phases that are formed. The results reveal that the use of the copper anodised layer prevented formation of brittle intermetallic compounds due to the direct FSW of 6061 aluminium alloy to copper and, as a result, enhanced the weld metallurgical and mechanical properties.

Dissimilar friction stir welding of 6061 Al to 316 stainless steel using Zn as a filler metal

“…FSW offers many advantages in the suppression of defects such as blow holes, segregation, cracks and generation of IMC, compared with traditional fusion welding [4]. These attractive advantages make FSW intensively used in dissimilar welding [5][6][7][8][9] and studies published on the FSW of Al to steel in butt joint and lap joint are in a considerable number. Xiong JT [10] fabricated the lap joints of aluminium and stainless steel by FSW with cutting pin.…”

“…Al/Cu FSW also face the problem of generating IMC layer [7][8][9]. To avoid this problem, Kuang BB et al [14] used Zn foil as filler metal to carry out friction stir lap welding (FSLW) of Al to pure Cu, as both Al and Cu could form alloys with Zn according to the phase diagram.…”

Effect of solid solution phase constitution on dissimilar Al/Cu FSW using Zn as an alloying element at the joint interface

“…Dissimilar fusion welding of Al/Cu forms different intermetallic compounds (IMCs) with high hardness and brittleness at the joint interface. Non-uniform distribution and non-homogeneity of IMCs in the weld zone are major causes of formation of micro-cracks [1] and pores [2] as well as deterioration of weld quality. The IMCs are also formed in dissimilar friction stir welding (FSW) process [2,3].…”

The effect of reinforcement type on the microstructure, mechanical properties, and wear resistance of A356 matrix composites produced by FSP

“…FSP has been invented based on friction stir welding (FSW) for the microstructure modification of materials [7,8], which results in improving their mechanical and wear resistance. FSW as a welding technique has been used to weld different Al [8,[13][14][15][16], Mg [7,17,18], and Cu [13,19] alloys, some of which are classified as practically unweldable alloys in use of conventional welding methods. Different surface composites have been produced with different types of reinforcing particles like SiC [7,20], TiC [21], Al 2 O 3 [22], CNT [23][24][25], TiO 2 [26], and B 4 C [27].…”